Have a lot/too much on my plate(informal): có quá nhiều việc phải làm. 

I would love to go to the zoo with you, but I have too much on my plate this weekend  

Be up to my ears in sth: ngập đầu với thứ gì, có nhiều thứ để giải quyết.(to be very , or to have more of something than you can)

We're up to our ears in decorating at the moment.

The cream of the crop: cái tốt nhất ( the best of a group of similar things or people).

The school's graduates are considered to be the cream of the crop and can get jobs whatever  they want to.  

This company is well-known as a good place to work and is always able to hire the cream of the crop of university graduates.

Not be one's cup of tea (informal): không phải sở thích của ai đó

Opera is not exactly my cup of tea.

Sell like hot cakes(informal): bán đắt hàng, chạy hàng.

The book has only just been published and copies are already selling like hot cakes in both Britain and America.

A fair-weather friend: người bạn khi tốt đẹp, khi khó khăn thì rời bỏ.

You need to be careful, George. I feel that he's just a fair-weather friend.

The early bird gets/catches the worm: trâu chậm uống nước đục; thành công sẽ đến với ai biết nắm bắt nhanh cơ hội.

If you see a job that interests you, apply as soon as possible. The early bird catches the worm.

Cash cow: món hàng/thứ mang lại nhiều lợi nhuận.

The movie studio saw the actress as a cash cow.

There are plenty of/more fish in the sea: có nhiều lựa chọn khác nữa.

It's too bad that your secretary quit, but there are plenty more fish in the sea.

Heart and soul: với tất cả tâm hồn, hết lòng, hết sức thiết tha(completely)

She put her heart and soul into a project aimed at helping deaf children.

She loves those children heart and soul.

Lend an ear: lắng nghe 1 cách chân thành

Whenever I have a problem, I talk to my best friend. She always lends a sympathetic ear.

Have sb's ear/have the ear of sb: được ai đó tin tưởng để đưa ra lời khuyên, ý kiến có sức ảnh hưởng

My professor has the ears of many business leaders, and gives them advice about the economy.

Have the blues(informal): cảm thấy buồn

I get the blues every time I hear that song.

In seventh heaven: rất vui, hạnh phúc.

I'd be in seventh heaven if I won the lottery.

To be up in the air: chưa chắc chắn, chưa được quyết định.

"Have you decided the destination yet?" "No, things are still up in the air."